They didn't want a lot of credit or attention — they didn't even leave their names. The family just wanted to do something good for shelter dogs in memory of their beloved dog, Marley, who recently passed away.

"Please help yourself to a tennis ball for you and your dog to play with," the note said. "Keep it or drop it back in the bucket for another dog to enjoy! Love this moment with your dog and enjoy this play time together in memory of our sweet Marley who absolute loved to play ‘ball.’"

"Marley loved to play ball and her family wants other pups to have some fun too!" the shelter wrote on Facebook.

Just imagine how happy so many shelter dogs would be if this became a common way to memorialize beloved family dogs. Considering there are over three million homeless dogs entering U.S. shelters every year, there's always a dog out there looking for a way to cheer up.